Characterization of Nanostructured Phases and Peculiar Phase Transitions in BNBT Lead-Free Piezoceramics
Submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT6) dense ceramics, from nanometric powder synthesized by sol gel auto-combustion at 500ºC and obtained by hot-pressing (800ºC-2h) and subsequent recrystallization at moderate temperature (1000-1050ºC-1h), have been studied. In-situ measurements at...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/108274 |
| Acceso en línea: | http://hdl.handle.net/10261/108274 |
| Access Level: | acceso abierto |
| Palabra clave: | Bismuth sodium titanate Barium Titanate Lead-Free Piezoelectric Ceramics Ferroelectrics Phase Transitions Shear Resonances |
| Sumario: | Submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT6) dense ceramics, from nanometric powder synthesized by sol gel auto-combustion at 500ºC and obtained by hot-pressing (800ºC-2h) and subsequent recrystallization at moderate temperature (1000-1050ºC-1h), have been studied. In-situ measurements at the shear mode of electromechanical resonance of non-standard thickness-poled shear plates as a function of the temperature show higher depolarization temperature than measurements at the radial mode of thin disks. Shear mode related material coefficients are measurable up to 160ºC, being k15≈30% and d15≈250 pC.N-1 at 130ºC. Depolarization is a complex phenomena caused by a ferroelectric (FE) macrodomains thermal randomization and a phase transition from the field-induced FE phase to a relaxor phase. The early stage of such a transition involves a non-negligible piezoelectricity arising most probably by the percolative coexistence of ferroelectric macrodomains in the resonator under the given stress field for each resonance mode. |
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